Calcuiatoh



Dec. l2, 1950 J, A, EsPlNOLA 2,533,569

CALCULATOR Filed Dec. 12, 1946 FIG.I.

FIG-4.

ATTORNEYS.

Patented Dec. 12, 1950 UNITED STATES RATENT OFFICE CALCULATOR J ovino A. Espnola, La Vega, Dominican Republic Application December 12, 1946, Serial N o. 715,763

(Cl. 23S-87) 1 claim. 1

This invention relates to an improved calculator or more particularly to a calculating de- Vice for assistance in or instruction in arithmetio.

It isA among the objects of this invention to providea calculator capable of instantly and accurately indicating the multiplication products of any numbers within its range, and of indicating the division products of certain numbers within its range. It is also an obje-ct to provide a calculator which is simple in operation. Another object is that of providing a calculator which is small, light, easily portable, and sufficiently sturdy to endure rigorous handling. A further object is provision of a calculator which may be economically constructed. An object also is to provide a device useful for instruction in arithmetic.

Other objects will be in part pointed out and in part implied hereinafter. These objects are achieved by my invention, suitable embodiments of which are described in the following specification and shown in the accompanying drawings. in which- Figure 1 is a side View of a calculator embodying features of my invention;

Figure 2 is a sectional View along lines 2--2 of Figure l;

Figure 3 is a perspective View of the barrel assembly of the calculator shown in Figures 1 and 2,;

Figure 4 is a perspective view of the cylinder assembly of the calculator;

Figure 5 is a perspective ViewV of one of the bands of the calculator;

Figure 6V is a side view of a modified form of cylinder embodying other features of my invention.

Referring toA that form of device shown in Figures 1 -5 inclusive, it will be seen to comprise a hollow cylinder or barrel l closed at one end by a cap 3 and having a window 2 extending longitudinally for the greater part of the length thereof. A cylinder 5 of slightly lesser diameter and of lesser length vthan barrel l is supported within barrel l. A knob I5 is iiXedl-y mounted at one end of cylinder 5 and adapted to protrude from barrel I when cylinder 5 is in place in barrel l. As shown in Figures l and 2, knob I6 may be made of similar shape and size as cap 3 so that when cylinder 5 is mounted in barrel l the assembly presents asymmetrical appearance.

On cylinder 5 is printed or engraved a table which consists of a plurality of lines and columns of numerals so arranged that both the first column of numerals at the left and the rst line of numerals at the top consist of a series of sequential numerals commencing with l at the upper left-hand corner; at the spaces corresponding to the rectangular coordinates of the primary linear and columnar numerals are placed numerals which equal the multiplication products of their respective linear and columnar numerals. For example, as shown in Figure 4, the line of numerals commencing at the left with 3 continues in the succession 6, 9, 12 which are the respectivemultiples of 2, 3, 4, etc. (the primary columnar numerals) by 3.

A plurality of bands 'I are supported between cylinder 5 and barrel l, Each of these comprises, as shown in Figure 5, a strip which may be formed of metallic material such as spring brass of a width approximately equal to the Width of one of the columns in table 6 and having an arcuate portion i of a diameter slightly greater than that of cylinder 5 and less than that of barrel l and of a length. such that it forms a-n unclosed loop having a gap slightly greater in length than the width of window 2. One end of band l is bent radially outward to .form a tab 9 which, when the band is in place in barrel l, extends through window l to provide a ringer grip. On the outside of band l, just beneath tab 9, is printed or inscribed one of the numerals of a series corresponding to the series of numerals in the first line to the top of table 6. There is, however, one less band than there are columns in table there being no band for the column headedv by the numeral l.

- The bands are aligned with the columns of table and arranged in numerical sequence so that the number of each band corresponds with the primary numeral in the column beneath the band. The diameter oi the curved portions 8 of the bands being but slightly less than the inside diameter of barrel l, band 'i will be held in position by frictional engagement with lthe inside of barrel i and by virtue of projection of the tabs 9 through window Z.

The shoulder i@ on the inner face of knob it is in frictional engagement with the inside of the rim of barrel l and the inside of the rim of cylinder 5 is in frictional engagement with the shoulder ll on the inner face of cap 3; thus are provided bearings for cylinder 5 at both ends of barrel I, maintaining the two elements in coaxial relation and permitting rotation of cylinder 5 within barrel l.

The multiplication operation will normally be commenced with all of the tabs s in their uppermost positions against the upper edge of window 2 so that bands l close all of window 2 for the blank space at the extreme left thereof (above the column headed by the numeral 1 on table El) to the right of this space in window 2 will appear the numerals on the outside of bands 1. To multiply, the knob l5 is rotated until there appears in the open portion of the window at the extreme left the numeral corresponding to the desired multiplicand. Then the tab of the band bearing the number corresponding to the desired multiplier is pulled down inte engagement with the lower edge of window 2, opening that portion of the window beneath the band and revealing the numeral corresponding te the product of the selected multiplicand and multiplier.

Other arithmetical operationsgsuch as division,

may also be accomplished with this device. Any

number which appears to the right oi the ,first column on table 6 ,may be divided by the number on the band above its column. Division is accomplished by pulling down the tab of the band whose number corresponds to the divisor and by rotating the knob until the dividend appears in that portion of the window beneath the lowered tab. The quotient then will appear in the extreme left-hand space. An estimate of the division products of other numerals than those appearing on table B may be achieved by interpolation. To accomplish this operation, the tab of the Iband whose numeral corresponds to the divisor is pulled down as normally, and the knob is rotated until the two numerals on either side of the desired dividend appear in the window beneath the lowered band. For example, to divide 78 by 9, pull down the tab of the band marked 9 and rotate the knob until the numerals 72 and 81 appear in the window beneath the lowered band. These are the two numerals in the column beneath this band which are on either side of the dividend '78. At the extreme left-hand portion of the window now appear the two numerals 8 and Qindicating that the quotient' is between 8 and 9, in other words, 8 and a fraction. For greater accuracy, since '78 is nearer to 81 than it is to 72, the cylinder may be rotated to such a point that 81 is more nearly centered in the window beneath the lowered tab than is 72. In the extreme left-hand portion of the window it will now appear that the numeral 9 is more nearly centered than is the numeral 8, indicating that Ythe quotient is nearer to 9 than to 8, in other words, in excess of 81/2.

As will be seen in Figure 1l, there are twelve columns numbered consecutively from I to l2 and there are as many lines numbered similarly for this particular embodiment. Therefore, Vthe largest numbers which may be multiplied are 12 times l2 and for division the dividends range `Y from 2 to 14.4. It will be understood, of course,

that any number of lines and columns may be provided, thereby increasing or limiting the range of the device as desired.

In Figure 6 is shown a modied form of cylinder of similar function as cylinder 5 of the embodiment previously described. This cylinder comprises spaced circumferential portions of different diameter; lower portions il, intermediate portions i2 on either side of each of said lower portions, and aV raised portion I3 between adjacent pairs of said intermediate portions. YThe raised portions I3 are of slightly lesser diameter than the interior of barrel I and are adapted to bear rotatively againstrbarrel I and to support the cylinder in coaxial relation thereto. Lower portions II are imprinted with the numerals of the columns of a table similar to table 6. Intermediate portions I2 furnish a bearing for the edges of the inside of bands 'I which are similar to those employed in the embodiment previously described. The bands 'I in place on the intermediate portions I2 between the raised portions I3 will be maintained in spaced relation to the lower portion II and to the inside of barrel I, minimizing the area of friction of the bands with the cylinder and the barrel to allow easy Y rotation of the bands.

As will be seen in Figure 2, cylinder 5 may be hollow to provide a storage space for a pencil, penknife, ruler, nail iile or other similar small tools. To provide access to this storage space, cap 3 is removable from barrel I and is held in position thereto by frictional engagement. Moreover, as shown in Figure 2, a pencil Sharpener I4 may be built integrally with cap 3 extending inwardly thereof intobarrel I and cylinder 5 when cap 3 is in closed position. A circular opening I5 in the end of cap 3 may be provided to allow entry of the end of the pencil for sharpening when the cap is in closed position. A clip t maybe provided near one end of barrel I to afford means of retaining the device and its contents-in a pocket of the apparel ofV theuser.

There is thus provided a calculator capable of instantly and accurately performing multiplication of all numbers within its range, of exactly dividing selected numbers within its range and Y oi approximately dividing all numbers within its range.

The efcacy of the device as an aid to learning multiplication is considerably enhanced by its novel structural features and upon the mechanical steps performed in its normal use. The bands which close sections of the window, for example, play this important role: after turning the knob to select the desired multiplicand, the additional operation of lowering the tab of the band whose number corresponds to the multiplier must b-e performed before the answer is revealed. This momentary withholding of the solution enforces a period of suspense wherein 'the student operator may attempt to arriveY at his own answer which will be compared to the correct answer presently to be revealed. Such an attempt by the student to make his own calculation will more deeply impress upon him the correct answer, thereby greatly accelerating the learning process. v

As many possible embodiments may be made of my invention without departing from the scope thereof, and as many modications may be suggested by varying conditions of use, it is to be understood that the matter herein contained is merely illustrative and in no way restrictive or limiting.

I claim:

A calculating device comprising a barrel having a longitudinally extending window, a cylinder within said barrel, said cylinder having sections of lesser diameter bearing the columns of a multiplication v table, sections of intermediate diameter at either side of said sections of lesserY diameter, and sections of greater diameter ber--V 5 6 and rotatable thereon to expose or conceal said UNITED STATES PATENTS table to view through said opening. Number Name Date JOVINO A- ESPINOLA- 5,746 Baranowski sept. 5, 1848 731,175 Goodman June 16, 1903 REFERENCES CITED 1,158,774 Beard Nov, 2, 1915 The following references are of record in the 1,293,392

Fassa Feb. 4, 1919 le of this patent: 1,720,499

Walker July 9, 1929 

